Hi, I have a HP Pavilion 15" laptop that occasionally misbehaves after a resume from suspend mode. The problem is obvious when the screen updates e.g. after moving the mouse and the window focus changing, or when a terminal scrolls, I get a ficker of random short horizontal white lines over the top of the windows that then disappear. These appear to be predominantly focused towards the top of the screen, although they do also occur lower down but less obviously. Soemtimes these artifacts don't disappear until the next update - I attempted to capture them, but of course that provokes another screen update and they disappear. When this problem occurs, suspending and resuming again doesn't appear to fix the issue - only a reboot does. Environment: 00:02.0 VGA compatible controller: Intel Corporation HD Graphics 620 (rev 02) (prog-if 00 [VGA controller]) DeviceName: Intel Kabylake HD Graphics ULT GT2 Subsystem: Hewlett-Packard Company HD Graphics 620 Flags: bus master, fast devsel, latency 0, IRQ 130, IOMMU group 1 Memory at a0000000 (64-bit, non-prefetchable) [size=16M] Memory at 90000000 (64-bit, prefetchable) [size=256M] I/O ports at 4000 [size=64] Expansion ROM at 000c0000 [virtual] [disabled] [size=128K] Capabilities: [40] Vendor Specific Information: Len=0c <?> Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00 Capabilities: [ac] MSI: Enable+ Count=1/1 Maskable- 64bit- Capabilities: [d0] Power Management version 2 Capabilities: [100] Process Address Space ID (PASID) Capabilities: [200] Address Translation Service (ATS) Capabilities: [300] Page Request Interface (PRI) Kernel driver in use: i915 Kernel modules: i915 Debian Bullseye (stable), Xorg 1.20.11, libdrm 2.4.104, intel xorg driver 2.99.917+git20200714. Kernel messages related to DRM: Linux version 5.10.0-19-amd64 (debian-kernel@xxxxxxxxxxxxxxxx) (gcc-10 (Debian 1 0.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2) #1 SMP Debian 5.10.149-1 (2022-10-17) ... i915 0000:00:02.0: [drm] VT-d active for gfx access checking generic (90000000 408000) vs hw (a0000000 1000000) checking generic (90000000 408000) vs hw (90000000 10000000) fb0: switching to inteldrmfb from EFI VGA Console: switching to colour dummy device 80x25 i915 0000:00:02.0: vgaarb: deactivate vga console i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem i915 0000:00:02.0: firmware: direct-loading firmware i915/kbl_dmc_ver1_04.bin i915 0000:00:02.0: [drm] Finished loading DMC firmware i915/kbl_dmc_ver1_04.bin (v1.4) [drm] Initialized i915 1.6.0 20200917 for 0000:00:02.0 on minor 0 ACPI: Video Device [GFX0] (multi-head: yes rom: no post: no) input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input6 fbcon: i915drmfb (fb0) is primary device Console: switching to colour frame buffer device 170x48 i915 0000:00:02.0: [drm] fb0: i915drmfb frame buffer device mei_hdcp 0000:00:16.0-b638ab7e-94e2-4ea2-a552-d1c54b627f04: bound 0000:00:02.0 (ops i915_hdcp_component_ops [i915]) snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915]) (NULL device *): firmware: direct-loading firmware i915/kbl_dmc_ver1_04.bin mei_hdcp 0000:00:16.0-b638ab7e-94e2-4ea2-a552-d1c54b627f04: bound 0000:00:02.0 ( ops i915_hdcp_component_ops [i915]) The last two lines repeat each time the system is suspended/resumed. No errors or warnings appear to be logged either from the kernel nor in the Xorg log file specific to i915 (there's the usual Xorg whinging about the system being too slow... so an i5-7200U 2.5GHz isn't fast enough for Xorg!) It feels like some setting within the Intel GPU hardware that controls memory access timing isn't being properly restored. Is this a known issue? Thanks. Russell. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!